Order: Saurischia - Suborder: Theropod - Infraorder: Unknown - Superfamily: Violent Wyverns - Family: Devil
Deviljho are powerful, nomadic Brute Wyvern that can be found just about anywhere. They can be considered to be the most violent of the class along with the most unpredictable of them.
Deviljho were once just seen inhabiting every environment found in the New World but now Deviljho can be found living everywhere in the world. Some of the areas they've been seen living in include the Deserted Island, Flooded Forest, Tundra, Sandy Plains, Volcano (3rd), Misty Peaks, Ancestral Steppe, Sunken Hollow, Volcanic Hollow, Frozen Seaway, Heaven's Mount, Primal Forest, Everwood, and Dunes.
The Deviljho easily assert themselves as Super predators that rival Elder Dragons in any conceivable habitat they find themselves and are challenged by little. The only things that challenge them are other Deviljho, some other powerful monsters on par with Elder Dragons such as Rajang, and Elder Dragons. The long-ago healed gashes visible in their sides suggest that they constantly engage in titanic battles against creatures both as vicious, powerful, and sizable as themselves, such as the heavily armored Uragaan, the lava-dwelling Leviathan Agnaktor, the "King of the Skies" Rathalos, the "Lord of the Seas" Lagiacrus, etc. These battles, of course, are simply due to the local monsters' defense of their turf, as the Deviljho prefer to feast on the more abundant and defenseless population of herbivores. Even so, they remain both large and powerful enough to dominate a large percentage of its encounters, minor or major. Deviljho can most commonly be seen feeding on herbivores such as Aptonoth, Rhenoplos, Slagtoth, and Popo. They are also known to feed on Bird Wyverns like Great Jaggi and large predatory monsters.
Deviljho are endowed with heavy, powerful muscles, giving them the strength to overpower their prey. Their mouths are filled with rows upon rows of sharp, jagged teeth. This allows the beast to tear flesh from a victim with ease. This feature also allows them to attack from a distance, using their giant lower jaw as a crude shovel, they can fling boulder-sized clumps of earth at their quarry. Their eyes are small and simple, suggesting their vision is rather poor, but their other senses such as smell may compensate for this. Their tails are long and powerful, but their main feature of note is its breath attack. At will they can breathe from their mouths a stream of a mysterious energy known as dragon. If their muscles swell, the skin will be stretched out to reveal the less flexible and tougher fibrous tissues that lie underneath the upper layer of skin, opened up by old scars.
When enraged, almost all of their muscles swell and they become both faster and stronger. At this point, old battle scars become visible on the outer membrane of their skin. During this time, the muscles (now swollen) are tougher than they would be otherwise, but the underside of their stomachs become more vulnerable to attack.
Deviljho are highly aggressive. Eating everything that they can fit into their mouths and fighting to the death with almost everything they come across. Little is known about the creatures' mating rituals and even less on how they raise their young. But it is said that Deviljho only mate when a male encounters a female by chance. Mating ends quickly due to the aggressive nature of Deviljho inevitably leading to a fight between the two should they stay in the same area for too long. Interestingly, Deviljho will secrete a special hormone in order to tell other Deviljho that they aren't in predator mode to avoid attacking each other.
The following information is a rough translation from the Hunter's Encyclopedia 3.
"A huge Brute Wyvern species that constantly wanders from one area to another, looking for prey. There are features and characteristics that gave the Deviljho a very brute character, and also because of these traits, the alias "Feared-Dragon" was given to it. It was also reported that it can prey the creatures around the region to extinction. Because of its high metabolism and body heat, Deviljho is in constant search for a food source (Leading it to live a nomadic lifestyle). It can live to almost every ecosystem, From the Hellish volcano, to the Frozen Tundra"
"When the Deviljho receives enough damage, Most of its body muscles swell into reddish, inflated muscles, revealing scars caused by previous battles against other monsters the Deviljho engaged with. It is said that the pain and damage caused by the violence during the battle further increases the plumpness and strength of its brutish body muscles. It is also known to breathe a strange substance similar to that of the Dragon element, which causes dragon blight."
"Deviljho have strong jaws and sharp teeth to crush the hard shell of large monsters. Deviljho is characterized by a number of fangs growing from its chin. Using its jaw, it can shovel into the ground and also hurl rocks this way. Of course, it is also used to prey on other monsters."
"Deviljho are complete carnivores, and will prey on all living things from small sized herbivores to large sized monsters. Because they are not tied to any particular ecosystem, they seem to migrate on instinct, constantly searching on prey. Deviljho maintains a consistently high body temperature along with its large size, therefore it expands a lot of energy. Predatory activity must be high to supply itself with energy, but its appetite is something that is far beyond imagination. In the past, the number of all living things in one area were drastically reduced to the verge of extinction, as reports came in that it was the result of Deviljho's predation. A Deviljho tends to accumulate fatigue rather easily, and hunger is quick to follow. Once it succumbs to fatigue, the saliva will settle in, and then its predatory activities begin. Its drool is said to contain special ingredients which softens the shell and skin of its prey. There are many details about its ecology that are unknown and it is still unclear to how they breed, or if there are any sexual differences."